Chicken Anti-Idiotypic Antibodies As an Alternative to the Antimicrobial Treatment for the Control of Escherichia coli K 88 in Domestic Animals

Antimicrobials have been widely used to control dirrheal infections in domestic animals. However, the misuse of these antimicrobials can lead to human health hazards. The purpose of this research was to evaluate the efficacy of anti-idiotypic antibodies that mimic Escherichia coli K88 antigens in combating diarreal infections in piglets. Polyclonal anti-idiotypic antibodies (Ab2) were produced in laying hens against several monoclonal (mAb1) and polyclonal (pAb1) antibodies that recognized Escherichia coli K88 fimbrial antigen. Preliminary evaluation showed that anti-pAb antibodies (Ab2) were superior to anti-mab antibodies. Therefore, the efficacy of two Ab2 preparations [Ab2 produced against rabbit anti-K88 IgG2a and its F(ab’)2] were evaluated following an intragastric administration to neonatal piglets challenged with E. coli K88. Partial protection (62.5% survival) was observed in the Ab2 treated piglets, while only 12.5 % of control piglets (no-Ab2) survived. Our results indicate that Ab2 are excellent surrogate antigens for immunization and could also be useful in the control of E.coli infection in piglets